Some Ubuntu, Linux Mint, Debian and Arch Linux (and probably other Linux distributions) users are experiencing problems with Dropbox. It seems that some recent Python update breaks Dropbox (it doesn't affect new installations though), resulting in the following error:

Starting Dropbox...Traceback (most recent call last):
File "dropbox/client/main.py", line 13, in
File "autogen_explicit_imports.py", line 13, in
File "ui/common/selective_sync.py", line 6, in
File "arch/__init__.py", line 28, in
File "arch/linux/tracing.py", line 8, in
File "hard_trace.py", line 6, in
File "client_api/connection_hub.py", line 21, in
File "client_api/kv_connection.py", line 23, in
File "pylinux/__init__.py", line 71, in
File "cffi/api.py", line 311, in verify
File "dropbox/overrides.py", line 398, in load_library
File "cffi/verifier.py", line 69, in load_library
File "cffi/verifier.py", line 154, in _load_library
File "cffi/vengine_cpy.py", line 124, in load_library
VerificationError: importing '/home/andrei/pylinux/__pycache__/_cffi__xa0c4f46bx1d95b4de.so': No module named _cffi__xa0c4f46bx1d95b4de

Simply reinstalling Dropbox doesn't fix this issue, but it is pretty easy to fix anyway.

To fix this Dropbox error in Ubuntu / Linux Mint / Debian, open a terminal and run the following commands:

sudo rm -rf /var/lib/dropbox/.dropbox-dist
dropbox start -i

This will remove the downloaded Dropbox binaries and redownload them. Once the download is done, Dropbox should start.

I'm not sure how to fix it for Arch Linux or other Linux distributions though, because the path is probably different but basically you must look for the .dropbox-dist folder (not the one in your home directory), remove it and run "dropbox start -i".